Question details

Calculating of actions of a SFC - CN 37-044 EN

Problem:Solution

HandlingTake the behaviour described above into consideration when updating systems with software versions V1.01 or V2.13 to software versions from V2.21.

Problems

General System InformationFor software versions from V2.2 1 the actions of a step are only computed after thefirst task cycle AFTER the step has been activated. For software versions up to V2.13actions were computed from the cycle in which the step was activated.

Example:A SFC runs in a task with a cycle time of T=1s.The initial step has a waiting time of 5s.In the application a counter is incremented in the initial step. After the 5s have elapsedthe follow-up transition switches.Behaviour in software versions up to V2.13: the counter is incremented to the value 5.Behaviour in software versions from V2.21: the counter is incremented to the value 4 asthe incrementing of the counter does not occur until the step running time of t=1s has elapsed.